Most of my fears (ladders, heights, thunderstorms, Red Sox fans, etc.) were developed in full adulthood. 

I was really scared to be sucked in by a black hole.
TerokNor
Coupled that with a viewing of Arachnophobia when I was way too young to understand the concept of 'horror comedy' and you have a kid who was terrified of killer spiders for years.
I also went through a phase when I was 4 or 5 when I was afraid to flush the toilet. I still flushed every time, but would run out of the bathroom as fast as I possibly could as soon as I pulled the handle!
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